What is THCA, does it get you high, and how does it turn into THC? This covers where the plant makes it, what a 2017 test on human CB1 locks found once the sample was checked for THC, how fast heat converts it in a vacuum oven and how much smoking converts, what happens when you swallow it raw, what studies in rats, shrews and mice found, and whether THCA shows up on a drug test.
The full answer
THCA vs THC: what's the difference?
THCA versus THC: what's the difference? THCA is the form the cannabis plant actually makes, and it barely fits the lock in your brain that THC turns, so on its own it doesn't get you high. I'm Justin Hartfield, and I've been selling cannabis for twenty-five years. Most of the THC in a cannabis flower is still THCA until someone heats it, and the heat from a lighter or an oven is what turns it into THC.
What is THCA?
What is THCA? THCA is tetrahydrocannabinolic acid, which is THC with an acid group, a carbon and two oxygens, still attached to its side. In 2004, a team in Japan found the gene for the enzyme that builds it, THCA synthase, and showed that it turns a precursor called CBGA into THCA. The plant makes and stores it in the sticky glands on its flowers and leaves, and in fresh plant material about ninety percent of the THC is still in this acid form. Hemp plants run a different enzyme on the same precursor and make CBD's acid instead.
Does THCA get you high?
Does THCA get you high? Not by itself, because it barely fits the lock. THC gets you high by holding down a brake your brain already has, a lock called CB1. In 2017, a team at the University of Auckland tested THCA on human CB1 locks in cells. They used a certified reference sample, checked it first, and found that even it was two percent THC. THCA bound the lock about sixty-two times more weakly than THC did, and at their highest dose the binding they saw matched what that two percent of THC would do by itself. A lab in Vienna had reported in 2014 that THCA bound about as tightly as THC, and the Auckland team thinks THC that formed in the sample explains results like that. In rats, THCA didn't lower body temperature or slow them down, two standard signs of a drug turning CB1.
How does THCA turn into THC?
How does THCA turn into THC? Heat knocks the acid group off as carbon dioxide, and what's left is THC, the shape that fits the lock. Chemists call this decarboxylation. In 2016, chemists at the University of Mississippi heated cannabis extract in a vacuum oven and timed it. Below about a hundred degrees Celsius, some THCA was still left after an hour. At a hundred and ten degrees, about two hundred and thirty Fahrenheit, it was nearly gone in thirty minutes, at a hundred and thirty in nine minutes, and at a hundred and forty-five in six. Smoking doesn't convert all of it. When forensic chemists in Basel simulated smoking in 2005, only about thirty percent of the THCA came out as THC. Time does the same job, only much more slowly. In dried flower kept in glass at room temperature, THCA had dropped to eighty percent of its starting level after twenty-five months.
Does raw THCA get you high if you eat it?
Does raw THCA get you high if you eat it? Probably not, because your body doesn't seem to do the job that heat does. In 2009, forensic toxicologists in Freiburg fed pure THCA to rats and found its breakdown products in their urine, but no THC. Swallowed THCA does reach the blood in people. In 2025 at Johns Hopkins, fifteen adults swallowed a hemp extract with roughly equal amounts of THC and THCA, and THCA, along with CBD's acid form, peaked in their blood at nineteen to twenty-five times the level of THC and CBD. That tells you the acid is absorbed well. It doesn't tell you THCA does anything once it's in the blood, and whether much of it reaches the brain hasn't been measured. A 2016 review pointed out that brain levels had been reported for several plant cannabinoids but not for THCA, and its author suspected the acid group keeps most of it out. Raw flower also isn't pure THCA, because part of it turns into THC on the shelf.
Does THCA do anything in the body?
Does THCA do anything in the body? In animals it does something. In 2013, a team in Canada gave tiny doses of THCA to rats, which then showed fewer signs of nausea, and to shrews, which vomited less. Oddly, a drug that blocks CB1 stopped the effect, even though THCA barely binds that lock, and the Auckland team lists that as an open question. In 2017, a team in Spain gave THCA to mice poisoned with a toxin that damages the striatum, a movement center in the brain, and it protected those nerve cells through a different receptor, called PPAR-gamma. I found no trial that has given people THCA on its own and measured whether it helps with anything, so the health claims for raw THCA rest on studies in rats, mice and cells.
Will THCA show up on a drug test?
Will THCA show up on a drug test? If you smoke it, yes. Smoking turns part of it into THC, and urine tests look for what your body makes from THC, a breakdown product called THC-COOH. THC made from THCA flower is the same molecule as THC from any other flower. The THCA that doesn't convert gets into your blood as well. In 2024, a forensic lab in Leipzig checked blood from more than eight hundred drivers with THC in it, and nearly half also had measurable THCA. I found no study that gave people flower sold as THCA and then ran a workplace drug test, but chemically there's nothing to tell that THC apart. My guess is that plenty of people buying THCA flower don't realize it tests like any other weed.
The whole film is on my site, linked below. Next: What are delta-8 and HHC?
What the studies show
Every claim in this answer, the study behind it, who was studied, and who paid for the research. “None listed” means the paper names no funder.
